An Improved AC Supply-Based Method for Measuring the Inductance Profile of SRM Using SOGI

The winding inductance of an electric motor is crucial for estimating its performance. In switched reluctance motors (SRMs), this inductance varies with rotor position and phase current, necessitating precise measurement for performance evaluation. This article introduces a sinusoidal excitation methodology for evaluating SRM winding inductance, focusing on measuring inductance profiles across different excitation currents without relying on costly devices, such as power analyzers, LCR meters, true rms meters, or specific power supplies, while maintaining high accuracy. A significant challenge in ac methods for inductance measurement is waveform distortion due to core saturation, which reduces accuracy. The proposed method addresses this by using a second-order generalized integrator (SOGI) filter to attenuate distortion-causing frequencies, thereby enhancing solution accuracy in saturation. The magnetizing power component is isolated from the total input power for inductance calculation. A finite-element analysis (FEA) of motor winding inductance and performance under both dc and sinusoidal excitation conditions is presented, comparing the analytical model with FEA solutions. Experimental results highlight the effectiveness of the proposed method, which delivers precise and comparable outcomes when tested against various methods in the literature and across different excitation currents.